1. Field of the Invention
This invention generally relates to a bicycle brake pad. More specifically, the present invention relates to a bicycle disc brake pad in which a friction member is bonded to a backplate.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle brake device. In particular, in recent years, bicycles have been provided with disc braking devices in order to improve braking performance.
Bicycle disc brake devices are provided for controlling and stopping the relative rotation of the bicycle wheels. Each disc brake device typically includes a metal disc brake rotor that rotates in unison with one of the wheels, and disc brake calipers with brake pads that selectively contact the disc brake rotor and apply pressure thereto to apply a braking force. Typical disc brake devices can be fluid actuated (i.e. by fluid pressure) or cable (mechanically) actuated
The disc brake pads normally apply a braking force to a wheel by clamping the disc brake rotor that rotates together with the wheel. Disc brake pads often have a sintered metallic dry-type friction member formed of copper-based metal, and a backplate to which the friction member is bonded. The backplate is often formed of steel such as stainless alloy and the like. These types of disc brake pads are conventionally and widely known (see, for example, Japanese Laid-Open Patent Publication No. H08-188769). In conventional disc brake pads having a sintered metallic friction member, the friction member is manufactured by simultaneously calcining the sintered metal and bonding the sintered metal to the backplate by a diffusion bonding method. Specifically, the sintered metal of the friction member is calcined onto a copper plating formed on the bonding surface of the backplate. When a brake pad is manufactured in this way, the copper plating layer and the backplate are bonded by chemical bonding that produces a metallic bond.
In conventional structures in which a friction member is bonded on a copper plated surface by a diffusion bonding method, a copper plating layer for chemically bonding to the backplate is formed on the backplate, and a friction member is sintered on the copper plating layer. Therefore, there is a problem concerning restrictions of the quality of the backplate inasmuch as material having the quality of a strong chemical bonding with copper must be used for the backplate. For example, when titanium alloy and the like containing titanium and titanium alloy is used for the backplate, the copper plating layer may peel from the backplate since copper and titanium have a weak chemical bonding power, thus producing concern that the backplate may separate from the friction member.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle brake pad. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.